Pre-meal glucose value generally refers to fasting glucose value, and the normal pre-meal range is between 3.9-6.1mmol/L. If the pre-meal blood sugar is lower than 3.9mmol/L, it means the symptoms of hypoglycemia, dizziness, weakness and chest tightness will appear, and the symptoms can be relieved by timely sugar supplementation treatment. When the pre-meal blood sugar is higher than 6.1mmol/L or lower than 7.1mmol/L, it belongs to the situation of abnormal fasting blood sugar, and this time, we should pay more attention to the low sugar diet, and it has not reached the diagnosis of type II diabetes. If the preprandial blood sugar is greater than 7.1mmol/L, it can be diagnosed as type II diabetes, which needs to be observed for about three months, and if the blood sugar is not well controlled, the oral medication for diabetes can be activated for treatment.